The main objective of this study is to compare the albumin turnover rate, distribution and external loss in a group of hemodialysis patients who are participating in the MMHD study funded by the NIH. We will establish baseline plasma albumin concentration and turnover rate, nutritional status, the levels of acute phase proteins in plasma and plasma albumin concentration for a period of 2 years and repeat measurements of albumin turnover either at the end of the 2 year period or following a change in plasma albumin concentration of 4 mg/ml or more. Measurement of nutritional status and the concentrations of albumin and acute phase proteins will be measured in all patients whose baseline albumin concentration is in the lowest quartile of quartiles. Serum albumin concentration will be determined monthly in the other 80% of patients whose baseline albumin values lie in the upper 3 quartiles in whom albumin turnover is not determined.